The present invention concerns an electric motor with an essentially cylindrical or conical or possibly disk-shaped rotor and with an interior space surrounded by this rotor and/or its stator, into which protrudes at least partially an epicyclic gear system, in particular a planetary gear system) driven by the electric motor. The electric motor includes a toothed power output element which meshes in the installed position with opposing teeth of a power input element of the epicyclic gear system.
An electric motor of this type with an epicyclic gear system designed as a planetary gear drive is known from DE-GM 85 13 219.5. Here, the sun gear shaft of this arrangement is joined with the rotor of the electric motor and thus forms the toothed output element of the motor. Meshing with this sun gear shaft in the installed position are planetary gears combined, for their part, in a carrier, which makes possible a gearing down. In addition, the planetary gears can also run inside a ring gear.
In manufacturing such an electric motor with epicyclic gear drive, i.e., such a drive motor, the motor manufacturer must usually assemble the individual drive parts, which means a significant logistical and assembly effort. During subsequent inspection, occurring defects normally require the disassembly of at least the drive parts and subsequent reassembly, with a corresponding additional expense.
From EP 0 111 350 A1, an electric motor is known with a conical or almost disk-shaped rotor whose stator magnets surround an inner space called a torus, which serves, however, in accommodating a brake rather than an epicyclic gear drive.
The object of the present invention is to provide an electric motor or drive motor of the type mentioned above in which assembly by the motor manufacturer and any search for defects are simplified.
In solving this problem, it is provided that the power input element of the epicyclic gear system which includes the opposing teeth is preassembled with additional drive parts into a unit and that the power input element of this unit can be engaged around the toothed power output element of the electric motor and preassembled therewith.
As a result, it is possible to preassemble practically the entire epicyclic gear system and also, if necessary, to preexamine it for defects so that a drive manufacturer can also be enlisted for this purpose. The motor manufacturer then only needs to push this assembled unit into the interior space of the motor in line with the amount that the epicyclic gear drive is supposed to extend into this interior space in the installed position, through which interlocking with the power output element previously assembled or already present there occurs. The motor and drive can then be additionally joined to each other. Above all, disassembly in the case of occurring defects is also correspondingly simple. The motor manufacturer thus has considerably reduced the expense related to the assembly of the epicyclic gear system which protrudes at least partially into the electric motor which he has manufactured.
It is appropriate here if the entire epicyclic gear drive is preassembled and is engageable with its power input element having the opposing teeth with the toothed power output element of the electric motor and can be especially releasably joined to the electric motor. This means that the motor manufacturer can order a practically complete epicyclic gear system and can join it to his electric motor without having to install individual drive parts in the interior of the electric motor. Prior to this final assembly, the epicyclic gear system and the electric motor can also be individually examined for defects, which means a further advantage since any defects can be found more quickly and directly assigned to the individual units.
The electric motor and the epicyclic gear system can be joined together, for example, via screws or the like, especially via screws running through the drive and/or the motor housing, or by gluing the housing parts contacting each other in the installed position. Thus, the motor manufacturer only needs to join the epicyclic gear system to the electric motor and then install the screws or carry out a gluing process during the joining together, which means considerable simplification and a corresponding saving of time compared to individual assembly of the individual drive parts to the motor.
An especially advantageous embodiment of the electric drive motor according to the present invention can be based on the toothed power output element of the electric motor being a sun gear shaft, which forms the output shaft of the electric motor and on which the opposing-teeth-exhibiting power input element or elements of the epicyclic gear system, especially the planetary gears of a planetary gear system, can be mounted in the axial direction. As a result, the planetary gears also automatically assume their installed position, namely, meshing with the sun gear shaft.
A modified embodiment can be based on the electric drive motor having an interiorly cylindrical rotor provided with inner teeth as the toothed power output element forming the ring gear of an epicyclic or planetary gear system and into which can be inserted the carrier-held planetary gears or similar opposing gears together with the other drive parts. Thus, if a planetary ring gear is used as the power output element of the electric motor, the basic idea of the present invention can still be realized and a preassembled gear drive unit can be used in which the final positive coupling between electric motor and epicyclic gear system is produced through the fact that the planetary gears with their teeth are inserted or pushed into engagement with the interior teeth of the ring gear and brought into their installed position.
A refinement of the arrangement in which the toothed power output element of the electric motor is the sun gear shaft of an epicyclic gear system can be based on the cantilevered sun gear shaft being joined in rotationally fixed fashion with the rotor of the electric motor, for example, through gluing, and carrying a bearing either directly or on a surrounding sleeve section rotationally fixed to or joined as one piece with the rotor. An axial continuation of the planetary ring gear of the epicyclic or planetary gear system fits on said bearing and is simultaneously mountable upon slipping the planetary gears over the teeth of the sun gear shaft. In this way, one has as the xe2x80x9cintersection pointxe2x80x9d between the electric motor and the epicyclic gear system, on the one hand, the teeth on the sun gear shaft and, on the other hand, the bearing preassembled with this shaft, at least two points thus coming into contact during pushing or plugging together, namely, the toothed elements, on the one hand, and the support point, on the other. It should be mentioned that the bearing, however, could be initially preassembled within the planetary ring gear and, upon joining together the epicyclic gear system and the electric motor, could arrive at the opposing support point in the area of the sun gear shaft.
In the assembled position, a sealing ring, especially an O-ring, can be provided between the bearing-surrounding continuation of the planetary ring gear and this bearing. As a result, one can keep lubricant from the gear system from getting into the motor. This sealing or O-ring can also be provided here already preassembled especially on the continuation of the planetary ring gear that comes into contact with the outside of the motor-side bearing upon shoving together the gear drive and motor.
A further advantageous refinement of the present invention which is especially advantageous and favorable for the precision involved in the cooperation of the electric motor with the epicyclic gear system can be based on the planetary ring gear belonging to the assembled unit of the epicyclic gear system having a centering element effective with respect to the interior space or a continuation of the interior space of the electric motor, especially a centering element effective with respect to the stator, which centering element arrives at its installed position upon joining or plugging together. A frustoconical or cylindrical centering element or centering surface positioned concentric to the middle of the motor and the gear drive can thus be provided appropriately on the outside of the planetary ring gear or a continuation of this planetary ring gear, which centering element utilizes the shape of the stator, arrives at its installed position upon joining or plugging together, and ensures the required accuracy and precision of the coaxial arrangement of the sun gear shaft and the planetary gears.
The centering element can be situated here in the installed position against the axially extreme gear-drive-facing edge of the inside of the stator. Located on the outside of the planetary ring gear, this centering element can be offset, viewed in the direction of insertion, with respect to the point of support and the end walls of the planetary gears facing the electric motor, which has the advantage that the joining or insertion process has progressed already relatively far before the relatively narrow-tolerance centering element needs to be fitted in place. In this way, at least the first part of the joining process can proceed with ease of motion.
Especially upon combination of a few or several of the above-described features and measures, it becomes possible to preassemble the electric motor and the epicyclic or planetary gear system each at a different location, whereupon these components forming the electric drive motor only need to be plugged together and attached to each other. The point of intersection can be composed here of a rotor-side bearing and a centering element so that the insertion or joining process is very simple. Defects can be detected and eliminated and later repairs carried out in correspondingly simple fashion before final assembly or even after this assembly.